Common Heart Failure Test May Be Flawed

A standard diagnostic test for heart failure is wrong in a subtle way that could lead to harm for some patients, researchers report. The test measures levels of brain natriuretic peptide (BNP), a hormone produced by heart muscle. More BNP is produced in heart failure because the heart progressively loses its ability to pump blood and then strains to get the work done. That's why cardiologists routinely measure BNP levels as they diagnose and treat the disease. However, the body makes different forms of BNP, noted lead researcher David C. Muddiman, a professor of chemistry at North Carolina State University in Raleigh. One is the "active" form, made under normal conditions, while another form is produced when the heart starts to fail. According to Muddiman's team, the standard test doesn't distinguish between those two forms. Using a high-tech method called mass spectrometry, "Our data shows for the first time that they are not measuring what they think they are measuring," he said. "They are not measuring the active form, the form that helps you." The findings appear in this week's online issue of the Proceedings of the National Academies of Science.